Hi Gang,
Let me pick the brain of the great collective and see what pops out.
I take EZNEC and put up a dipole for 20 meters at about 1/2 wl in
the air and I have a set of patterns that look like what I would expect to
see.
What happens if the dipole is not working against a normally flat
surface like when it is on top of a mountain?
My field day site is at about 6800' and drops off from that altitude
to about 1100' in a radius of about 270 degrees and about 250' from the
proposed antenna site. If I mount the antenna on this plateau on a short
mast (20') do I still have the low angle of attack that I would have at that
5700' drop off or is it still primarily effected by the 20' height above the
near field ground? Is there anyway to model this?
Don't get me wrong, I know the site works well I am just trying to
understand what is going on.
Anyone care to give me a bit of a readers digest version of an
answer as I am not an engineer, just a long time ham with questions. ;>)
My own best guess is that I have some residual effect from the near
field because of the proximity to ground so I get a pretty vertical angle of
attack for at least one lobe. In the far field ground which is sooooo far
away I an thinking I get the good clear field of attack on the horizon and a
lot of lobes from the various reflected signals/waves (Frenzal Effect?)so it
performs well. How close am I?
Michael Baker K7DD
k7ddmjb@qwest.net
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